CXLE82131XK is a high-precision buck constant current driver chip designed specifically for LED lighting, suitable for non isolated buck power supply solutions with a full input voltage range of 85Vac~265Vac. The chip operates in inductor current critical continuous mode and integrates a 500V power switch internally. Combined with advanced demagnetization detection technology and high-voltage JFET power supply architecture, it does not require external VCC capacitors and starting resistors, greatly simplifying peripheral circuit design and reducing system costs and volume.
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[ CXLE82131XK ]"
High performance LED constant current driver chip CXLE82131XK detailed explanation‐ JTM-IC Technology Analysis and Application Guide
In today's world where LED lighting is gradually becoming mainstream, efficient, stable, and low-cost driving solutions are particularly important. As a technology-based enterprise specializing in the design and supply of power management chips, JTM-IC（jtm-ic.com）The CXLE82131XK high-precision step-down LED constant current driver chip launched is a highly integrated solution tailored for LED lighting systems. This article will comprehensively analyze the characteristics, technical principles, application design, and protection mechanisms of the chip, helping engineers better understand and apply the chip.
1、 Overview of CXLE82131XK chip
CXLE82131XK is a high-precision buck constant current driver chip designed specifically for LED lighting, suitable for non isolated buck power supply solutions with a full input voltage range of 85Vac~265Vac. The chip operates in inductor current critical continuous mode and integrates a 500V power switch internally. Combined with advanced demagnetization detection technology and high-voltage JFET power supply architecture, it does not require external VCC capacitors and starting resistors, greatly simplifying peripheral circuit design and reducing system costs and volume.
The chip is equipped with a high-precision current sampling circuit and, combined with constant current control technology, can achieve± 5% output current accuracy, with excellent line voltage regulation and load regulation. Whether it is fluctuations in input voltage or changes in inductance and LED operating voltage, the output current can remain stable, ensuring the consistency and reliability of the lighting system.
2、 Core features and advantages
· highly integratedInternally integrated 600V ultra fast recovery diode and 500V power MOSFET, significantly reducing the number of peripheral devices.
· No auxiliary power supplyAdopting high-voltage JFET power supply technology, there is no need for VCC capacitors and starting resistors, resulting in a simpler system structure.
· Wide voltage adaptationSupports 85Vac~265Vac global universal input voltage, suitable for various LED lighting scenarios.
· High precision constant currentOutput current accuracy up to± 5% to ensure uniform and consistent LED brightness.
· Comprehensive protection mechanismEquipped with LED short circuit protection and chip overheating regulation function, it enhances system reliability.
· Compact packagingAdopting ESSOP6 packaging, suitable for compact lighting design with limited space.
3、 Internal structure and working principle
CXLE82131XK integrates internal circuit modules such as VCC power supply module, undervoltage protection, overheating regulation, constant current control, leading edge blanking, and current detection. After the system is powered on, the bus voltage supplies power to the chip through the HV pin. When the voltage reaches the turn-on threshold, the control circuit starts working. The chip achieves constant current control by detecting the peak current of the inductor cycle by cycle. The CS pin is connected to an external sampling resistor, which is compared with the internal 0.373V threshold. When the CS voltage reaches the threshold, the power transistor is turned off, thus achieving precise current regulation.
The formula for calculating output current is:
The RCS is an external sampling resistor, which is designed flexibly and easy to adjust the output current.
3.1. working principle
3.2. Internal Structure
4、 Design of Energy Storage Inductors and System Frequency
CXLE82131XK operates in critical conduction mode, and the system frequency varies with the input voltage. The choice of inductance directly affects system performance and efficiency. The inductance calculation formula is as follows:
To avoid the system entering intermittent or continuous mode, it should be ensured that the shutdown time is between the minimum demagnetization time (1.3μ s) and the maximum demagnetization time (250μ s) set by the chip to ensure constant current accuracy.
5、 Detailed explanation of protection function
The CXLE82131XK has multiple protection mechanisms to ensure the safe operation of the system in various abnormal situations:
· LED short circuit protectionWhen the output is short circuited, the system automatically enters a 4kHz low-frequency working mode with extremely low power consumption to avoid device damage.
· Overheating regulation functionWhen the surface temperature of the chip exceeds 120 ℃, it automatically reduces the output current, controls the temperature rise, achieves temperature closed-loop regulation, and improves the long-term reliability of the system.
6、 PCB design suggestions
A good PCB layout is the key to ensuring system stability and EMI performance:
· CS sampling resistorThe power ground wire should be short and thick, routed separately from the chip ground, and summarized to the bus capacitor ground. CS pin copper can enhance heat dissipation.
· HV pinKeep away from CS and other low-voltage signal pins to avoid noise interference.
· Power LoopMinimize the loop area between power inductors, power tubes, bus capacitors, freewheeling diodes, and output capacitors as much as possible to reduce EMI radiation.
· DRAIN pinIncrease the area of auxiliary copper to enhance the heat dissipation capability of the chip.
7、 Typical application scenarios
CXLE82131XK is widely used in various non isolated LED lighting power supplies, including:
· LED candle lamp
· LED bulb light
· Indoor lighting such as tube lights and panel lights
· Other LED lighting fixtures that require high-precision constant current drive
Its high integration, high reliability, and simple peripheral design are particularly suitable for compact lighting products that have strict requirements for cost and volume.
8、 Encapsulation pin function and ordering information
The CXLE82131XK is packaged in ESSOP6, which is compact in size and has good heat dissipation performance. The order model is CXLE82131XK, packaged in braided tape, with 5000 pieces per plate, making it convenient for automated production.
For detailed packaging dimensions and pin definitions, please refer to the technical manual or visit the JTM-IC official website（jtm-ic.com）Get the latest information.
9Electrical Characteristics
Electrical parameters
10、 Conclusion
CXLE82131XK, as a highly integrated, high-precision, and reliable LED constant current driver chip, has become the preferred solution in the field of LED lighting driver due to its simple peripheral circuit, comprehensive protection function, and excellent performance. JTM-IC will continue to be committed to providing high-performance power management chips and technical support to the market, helping the LED lighting industry develop towards efficiency, intelligence, and reliability.
For more product details, technical support, or sample requests, please visit the JTM-IC official website:jtm-ic.com.
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